Answer:
632.8 nm is the wavelength (in air) of red light from a helium neon laser.
There is 4000 balls in the earth of the world why is that so hard for you
<span>So we want to know what statement is an accurate description of vibrations. So humans can hear sound frequencies from 20-20000 Hz. Below 20 Hz is infra sound and above 20000 Hz is ultra sound. Humans cant hear both infra sound and ultra sound so the correct answer is A.</span>
<span>The energy of a single photon is given by E = hc/lambda, where h is Planck's constant, c is the speed of light, and lambda is the wavelength.
Plugging the values in gives E = 6.63E-34 x 3.00E8 / 700E-9 = 2.84E-19 Joules
Now one mole of substance is equivalent to 6.02E23 particles, so one mole of these photons will be:
2.84E-19 x 6.02E23 = 1.71E5 Joules</span>
It's definitely not B or C. There are things missing from A and D so we can't narrow it down any farther.